Clinical characteristics and treatment outcomes of adult acute promyelocytic leukemia in the West Bank of Palestine: a single-center retrospective study

Background: Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML), accounting for 5–20% of AML cases and characterized by a high risk of early mortality, most commonly due to hemorrhage secondary to disseminated intravascular coagulation (DIC). The introduction of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has transformed APL into a highly curable disease, with survival rates approaching 90% despite its historically poor prognosis. Data on APL outcomes in Palestine are rare. This study aimed to describe the clinical characteristics, treatment-related complications, and mortality in adult APL patients treated at a tertiary cancer center in Palestine, and to explore factors associated with early death and poor prognosis. Methods: We conducted a retrospective cohort study of 30 adult patients (≥18 years) diagnosed with APL between January 2016 and June 2024 at An-Najah National University Hospital (NNUH), West Bank, Palestine. Low-risk patients received ATRA plus ATO, whereas high-risk patients received ATRA in combination with anthracycline-based chemotherapy. Demographic, clinical, and laboratory data, treatment details, complications, and outcomes were abstracted from medical records. Early death was defined as death within 30 days of diagnosis. Continuous variables were summarized as medians with interquartile ranges (IQRs), and categorical variables as frequencies and percentages. Group comparisons used the Mann–Whitney U test for continuous variables and the chi-square test or Fisher’s exact test for categorical variables. Results: Thirty patients (15 males, 15 females) with a median age of 37 years (range, 18–79) were included. According to the Sanz risk score, 9 (30.0%) were low-risk, 13 (43.3%) intermediate-risk and 8 (26.7%) high-risk. Most patients presented with preserved performance status (ECOG 0–1). Median baseline values at diagnosis were: hemoglobin 9 g/dL, white blood cell (WBC) count 4.8×10⁹/L, platelet count 18.1×10⁹/L, absolute neutrophil count 0.95×10⁹/L, prothrombin time (PT) 17.2 seconds, fibrinogen 142.5 mg/dL and D-dimer 30.9. The early death rate (EDR) was 13.3% (4/30): one patient died before induction and three died during induction; all early deaths were due to hemorrhage related to DIC. Among the 26 patients who survived beyond 30 days and completed induction, all achieved complete remission (CR); approximately two-thirds achieved CR after the first induction cycle and the remainder after a second cycle. The median time to hematologic remission was 35 days. During consolidation and maintenance, one patient died during consolidation and one died after completing maintenance from a non-leukemia-related cause. No relapses were observed, and no patient required hematopoietic stem cell transplantation by the end of follow-up. Higher WBC (p = 0.038) and prolonged PT at diagnosis (p = 0.033) were significantly associated with early death; hemoglobin, ANC, platelets, fibrinogen, and D-dimer were not. Conclusions: In this single-center Palestinian cohort, APL outcomes with ATRA-based protocols were comparable to those reported from high-resource settings, with high remission rates and no observed relapse during follow-up. Early mortality, driven by hemorrhagic complications, remained the main obstacle to cure and was associated with higher leukocyte counts and more pronounced coagulopathy at diagnosis. These findings highlight the importance of timely diagnosis, immediate initiation of ATRA, and intensive supportive care in resource-limited settings, and support the need for larger multicenter studies in the region.